1. Field of the Invention
This invention relates to the shaping of glass sheets, particularly those of non-rectangular outline, to conform to the shape of bending molds having one or more shaping rails of outline configuration conforming to the shape desired for glass sheets to be bent. In the loading of such molds, it is important that glass sheets, particularly those of nonrectangular outline, be aligned precisely with respect to the outline of the mold shaping surface to which the glass is to conform. Accordingly, in the past, stops have been provided in close proximity to the outline shaping surface of the mold to assist in the proper alignment of glass sheets relative to the upwardly facing shaping surface of the outline mold. Under such circumstances each mold of a particular pattern was provided with a stop arranged and constructed in a manner unique for that particular pattern.
It would be beneficial to the glass sheet bending art to develop universal stops capable of use with molds of different peripheral outlines used to bend glass sheets of different outlines to different configurations and depth of bend required for different production patterns. Under such circumstances, the complicated storage and inventory problem required to maintain a separate supply of replacement stops for each pattern of molds would be eliminated.
2. Description of Patents of Interest
Stops have been used in many arrangements relative to glass sheet shaping apparatus. The patents described hereinafter represent many uses of glass edge alignment stops on glass sheet shaping molds.
U.S. Pat. Nos. 2,111,392 and 2,261,023 to Galey and 2,297,315 to Owen disclose stops that are fixed in position relative to a glass sheet bending mold to fix the position of a flat glass sheet when mounted for bending.
U.S. Pat. No. 2,330,349 to Galey provides stops fixed to the opposite ends of a sectionalized mold to guide the original positioning of a flat glass sheet onto the mold for bending. The stops continue to engage the ends of the glass sheet as the mold closes to help shape the glass sheet to the shaping surface defined by the mold.
U.S. Pat. No. 2,518,951 to Smith discloses stop members in the form of loosely supported blocks of asbestos or the like that are less harmful to glass sheet edges than the metal outline molds to which they are attached.
U.S. Pat. No. 2,551,607 to Jendrisak discloses stops comprising a ceramic roller rotatable on a frame that is pivotally attached to an outline mold for shaping glass sheets. The pivotable frame is spring loaded and means is provided to tension the spring so as to control the bias of the stops against the opposite ends of a glass sheet mounted on the outline mold for shaping.
U.S. Pat. No. 2,736,140 to Black discloses glass edge engaging members 360 that are provided with a bracket 361 rigidly mounted upon a shaping rail 325. A screw bolt 362 is threaded through the bracket plate 361. A small plate or disc is mounted on the inner end of the screw bolt 362 for slight pivotal movement in order that the disc may conform to the edge of the glass sheet when the latter is mounted on the shaping rail. The adjustment of the screw bolt 362 relative to the bracket 361 determines the location of the glass edge engaging surface of the disc relative to the shaping rail. There is no indication that the disc is mounted to the screw bolt in any other arrangement than concentric thereto.
U.S. Pat. No. 2,695,476 to Jendrisak and U.S. Pat. No. 2,729,032 to White disclose outline molds that have glass edge engaging members that pivot inward to follow the edges of the glass sheet as it sags toward the outline mold. The glass edge engaging members must be removed manually to remove the bent glass sheet from the mold. Other patents showing this feature include U.S. Pat. Nos. 2,744,359; 2,758,422; 2,774,189; 2,798,338 and 2,859,561, all to Jendrisak.
U.S. Pat. Nos. 2,814,164 and 3,089,319 to Carson and White disclose outline molds having universally pivotable stops that follow and engage pointed tips at the opposite longitudinal edges of glass sheets supported for bending on the outline mold to control tip overbending as well as positioning.
U.S. Pat. No 2,840,953 to Black and U.S. Pat. No. 3,023,542 to Babcock disclose bimetal actuators attached to glass edge guide members to change the location of the guide members in response to a change in temperature during the bending cycle. When the mold is cool, the bimetal actuators position the edge guides into proper positions for aligning a glass sheet edge. When the mold is heated to heat soften the glass, the bimetal actuators move the edge guide members relative to the engaged glass edge, thus either losing the contact between the guide members and the glass sheet edge that maintains the glass in proper mold alignment or forcing the glass into more intimate mold contact as the assembly is heated.
U.S. Pat. Nos. 2,901,866 and 3,162,523 to McKelvey and U.S. Pat. No. 3,103,430 to Jendrisak disclose outline molds with counterweighted, pivoted glass engaging members that pivot against the glass sheet edge as the glass sags toward the shaping surface of the outline mold. No provision is made to disengage the glass edge after the glass bend is completed except for manual operation.
U.S. Pat. No. 3,060,708 to Stickel discloses a sectionalized mold having glass edge engaging members mounted to move away from the glass edge as the mold sections close to provide a substantially continuous outline shaping surface. The alignment is lost as soon as the engagement members disengage from the glass edge.
U.S. Pat. No. 3,220,822 to Jendrisak discloses sectionalized outline molds having a pivoted end portion for each end mold section that follow the ends of the glass sheet as the latter shortens from a flat shape to a shape curved in elevation. Manual operation is also required here to separate the end portions from the bent glass sheet.
U.S. Pat. No. 3,230,067 to Carson and Stickel discloses an outline sectionalized shaping mold comprising pivotally supported shaped members that serve as both edge guides and supports for the flat glass sheet that rotate outwardly from the guided side edges as the mold closes and the glass sheet sags to shape. Disengagement of the glass edge as the glass sheet sags permits the likelihood of glass sheet misalignment during shaping.
U.S. Pat. No. 4,272,275 to Reese is concerned with glass edge alignment members that are supported in positions to engage the edge of one or more glass sheets mounted on an outline mold for sag bending during a sag bending step and are released from said supported positions suddenly and automatically just prior to removing the sag bent glass from said outline mold. The glass edge alignment members after said release are supported relative to said outline mold in positions remote from said glass edge to avoid rubbing the glass edge thereagainst during removal of the bent glass from the outline mold.
None of the patents discussed previously provide solutions to the problems of inventory storage and application of one stop construction for molds providing different patterns.